What do you think about Issac Asimov's "Lije Baley abd R. Daneel Oliwav" book series?

Lots of fun, and very nice mysteries. In the Empire books there is a throw away line identifying a rather nasty theocracy as a planet once known as Baley's World. Interesting tie-in, but Asimov was in the process of making all his novels and many of his short stories interconnected when he died.